A diverse school district hugging the eastern border of Washington, D.C., Prince George's County, has introduced rigorous hiring methods and other practices to boost the quality of leadership in its 198 schools. In so doing, the district has also earned a spot among the pioneers in efforts nationally to ensure that public schools are led by the best principals possible. "We think the most critical interaction in schools is between the teacher and the student, but second to that is leadership in the building," says Douglas Anthony, director of human capital management for the county. Prince George's County is one of six school districts taking part in a six-year, $75 million initiative to establish strong principal "pipelines." The key idea behind the initiative is that obtaining effective principals requires four essential elements: principal standards, high-quality training, selective hiring, and a combination of solid on-the-job support and performance evaluation, especially for new hires. These may seem like common sense, but until recently, leadership was an afterthought for most districts and, as a consequence, important pipeline elements were either insufficient or missing altogether. Now, several factors are changing the old scenario. One is government policy. Another factor is research. These factors combined have educators and policymakers looking intently at what they can do to promote school leadership.